The application of Mineral sizer in open-pit mines
Introduce
In recent years, with the transformation and upgrading of the coal industry, the requirements for efficient and environmentally friendly coal development have been increasing day by day. More and more lignite produced by open-pit coal mines is sold to coal chemical enterprises for further deep processing. The requirements for product particle size in the coal chemical industry are extremely strict. Generally, the particle size is required to be between 25 and 70mm. If the particle size is too large, it will clog the furnace and make subsequent deep processing impossible.
Mineral sizer is currently a relatively mature product applied in coal crushing. Due to its large processing capacity and low crushing rate, it has been widely recognized by coal users. In response to the unique problem of difficult crushing of frozen block materials in open-pit mines and the special low-temperature working environment, traditional crushing equipment is not applicable. However, Mineral sizer, with its distinctive crushing principle and adaptability, not only effectively solves the crushing problem of frozen block materials but also operates stably in low-temperature conditions, ensuring the continuity and efficiency of the coal processing process.
The structure of Mineral sizer
The Mineral sizer is driven by dual motors. Through a transmission system consisting of two motors, couplings and reducers, it respectively drives two sets of independently rotating toothed rollers to crush large pieces of material. Torque is transmitted between the reducers and the crushing toothed rollers by couplings. The crushing toothed rollers and the transmission system are respectively connected to the overall frame, minimizing the vibration of the equipment to the greatest extent. The overall structure of the Mineral sizer mainly consists of the crushing toothed roller as its working component. The tooth shape structure determines the process performance of the entire machine.
Improvement of the toothed roller structure
The structure of traditional crusher toothed rollers
The traditional toothed roller crusher with an output particle size of 70m generally adopts a toothed ring structure or a toothed plate structure. The gear ring structure is stable and highly reliable. However, the drawback is that the crushing teeth are not easy to replace after wear and must be returned to the factory for major repairs, which cannot be completed on site.
The traditional toothed plate structure is mainly connected by high-strength bolts and tooth seats, with a relatively small load-bearing capacity, and is mainly applied in the crushing operation of clean coal. The open-pit mining crusher needs to have both high reliability and strong replaceability. Therefore, the tooth plate connection structure needs to be redesigned to ensure the stable operation of the equipment.
Mineral sizer toothed roller structure
To fundamentally improve the drawback of inconvenient replacement of traditional tooth plates, the new mineral sizer tooth plate design adopts a single-sided dovetail groove installation method. This design, through a meticulously polished inclined surface structure, forms a perfect complementary and fitting relationship with the insert strip clamping block.
During the assembly process, the insert strip clamping block is precisely embedded into the dovetail groove of the tooth plate first, and the initial positioning is achieved through the interlocking effect of the inclined surface. Then, the entire broken tooth plate is smoothly installed onto the tooth plate fixing seat, ultimately constructing a tight and reliable surface-to-surface connection system.
The change in the installation method of the Mineral sizer gear plate has also altered the functional positioning of the bolts. In the traditional design, the bolts had to directly bear various external forces generated by the crushing operation. However, after optimization, the bolts are only responsible for fixing the insert strip clamping blocks, significantly reducing their own force burden and fundamentally avoiding the problem of the fixed locking bolts breaking due to excessive load. It also eliminates the situation where the tooth plate falls off due to bolt failure or is difficult to disassemble and replace due to bolt rust and other reasons.
In addition, all the crushing tooth plates are designed with practical convenience in mind in terms of size. The length and weight are both controlled within a reasonable range that is convenient for manual operation. More importantly, the tooth plates have a high degree of interchangeability.
When some tooth plates of the mineral sizer are worn or damaged during operation, there is no need to disassemble the entire tooth plate structure. Only the damaged single tooth plate needs to be replaced independently, which greatly simplifies the maintenance process and enhances the continuous operation capacity of the mineral sizer.
Improvement of tooth profile
Due to the characteristic of relatively large particle size of open-pit mining materials, the tooth profile of the mineral sizer tooth plate has also been reasonably optimized and designed. The tooth profile is arranged in the circumferential direction, adopting a form of alternating large and small teeth. Under the premise of ensuring the particle size of the output material, it can effectively enhance the meshing capacity of the tooth roller on the material, thereby improving the processing capacity of the mineral sizer, reducing the wear of the tooth roller, and prolonging the service life of the tooth plate.
The usage effect of Mineral sizer
The use of the original equipment
The raw coal mining in coal mines adopts the semi-continuous mining process of single-bucket trucks. The raw coal has a large particle size, a large amount of gangue and high hardness. Raw coal is first crushed to less than 300mm by the No. 2 crushing station, then crushed to less than 70mm by a ring hammer crusher, and then transported to the coal storage bin by the transfer belt. After screening, the final products with a diameter of 25-70mm are sold to chemical enterprises. The original ring hammer crusher has the following problems after long-term use:
① The over-crushing rate of the product is high and the lumping rate is low, which seriously affects the economic benefits of the enterprise
② The pin shafts, hammer heads and grates are severely worn and often need to be replaced and maintained, resulting in a large amount of repair work
③ The equipment has a high failure rate and high maintenance costs.
The use of Mineral sizer
Technical improvements are urgently needed on site to reduce the operating costs of the enterprise and the labor intensity of workers, and to ensure the normal operation of the production system. The user eventually chose a Mineral sizer to replace the original ring hammer crusher.
① Since the Mineral sizer was put into use, the equipment has been operating stably, and the particle size of the output products has been significantly improved. The over-crushing rate is low and the caking rate is high. Through data comparison, it can be seen that the difference in qualified products before and after equipment replacement is 18.2%, which has significantly increased the output of qualified products and created great economic benefits for the enterprise.
② In addition, as the Mineral sizer performs stretching and shearing crushing on materials at a relatively low rotational speed, the equipment operates stably with minimal vibration and noise, and is environmentally friendly. The Mineral sizer gear plate has high wear resistance, and the fastening bolts are not easy to loosen, which reduces a lot of maintenance time, lessens the labor intensity of workers, and greatly lowers the later maintenance cost of coal mines.
③ Practical experience has shown that Mineral sizer has greater technical advantages over ring hammer crushers in crushing frozen blocks from open-pit coal mines. It features large processing capacity, low overcrushing rate, high reliability and low maintenance requirements, achieving good application results.
Conclusion
With the transformation and upgrading of the coal industry, it is an inevitable trend to vigorously develop coal chemical industry. The coal chemical industry has strict requirements for the particle size of coal, which poses higher demands on crushing equipment.
By optimizing the structural type and material of the toothed roller and taking low-temperature resistant measures for the transmission system, Mineral sizer has successfully completed the crushing operation in open-pit coal mines. It features a high block formation rate, low maintenance, and obvious technical advantages, with broad application and promotion prospects.
